Characterisation of bacteria isolated from the stingless bee, Heterotrigona itama, honey, bee bread and propolis.

Mohamad Syazwan Ngalimat,Suriana Sabri,Raja Noor Zaliha Raja Abd Rahman,Mohd Termizi Yusof,Amir Syahir

doi:10.7717/peerj.7478

Abstract

Bacteria are present in stingless bee nest products. However, detailed information on their characteristics is scarce. Thus, this study aims to investigate the characteristics of bacterial species isolated from Malaysian stingless bee, Heterotrigona itama, nest products. Honey, bee bread and propolis were collected aseptically from four geographical localities of Malaysia. Total plate count (TPC), bacterial identification, phenotypic profile and enzymatic and antibacterial activities were studied. The results indicated that the number of TPC varies from one location to another. A total of 41 different bacterial isolates from the phyla Firmicutes, Proteobacteria and Actinobacteria were identified. Bacillus species were the major bacteria found. Therein, Bacillus cereus was the most frequently isolated species followed by Bacillus aryabhattai, Bacillus oleronius, Bacillus stratosphericus, Bacillus altitudinis, Bacillus amyloliquefaciens, Bacillus nealsonii, Bacillus toyonensis, Bacillus subtilis, Bacillus safensis, Bacillus pseudomycoides, Enterobacter asburiae, Enterobacter cloacae, Pantoea dispersa and Streptomyces kunmingensis. Phenotypic profile of 15 bacterial isolates using GEN III MicroPlate™ system revealed most of the isolates as capable to utilise carbohydrates as well as amino acids and carboxylic acids and derivatives. Proteolytic, lipolytic and cellulolytic activities as determined by enzymatic assays were detected in Bacillus stratosphericus PD6, Bacillus amyloliquefaciens PD9, Bacillus subtilis BD3 and Bacillus safensis BD9. Bacillus amyloliquefaciens PD9 showed broad-spectrum of antimicrobial activity against Gram-positive and Gram-negative bacteria in vitro. The multienzymes and antimicrobial activities exhibited by the bacterial isolates from H. itama nest products could provide potential sources of enzymes and antimicrobial compounds for biotechnological applications.

Highlights

Stingless bee nest products, such as honey, bee bread and propolis have bright economic potentials (Jacobs et al, 2006; Jones, 2013)
Bacterial isolation The Total plate count (TPC) was determined after 1–3 days of plate incubation to promote the growth of cultivable bacteria
The TPC of propolis ranged from 6.3 Â 103 ± 5.5 Â 102 to 1.8 Â 104 ± 5.8 Â 104 colony forming units per gram, while those recorded for honey samples ranged from 0.0 to 8.0 Â 103 ± 1.0 Â 103 cfu/g

Summary

Introduction

Stingless bee nest products, such as honey, bee bread and propolis have bright economic potentials (Jacobs et al, 2006; Jones, 2013). Stingless bee nest products, such as honey, are rich in antimicrobial activities due to its high sugar concentration, acidity, hydrogen peroxide (H2O2) and phytochemical compounds, which are unfavourable for growth of several microorganisms (Sinacori et al, 2014). Regardless of these antimicrobial activities, some microbes, such as bacteria, can still be found in honey (Yaacob et al, 2018), pollen (Gilliam, Roubik & Lorenz, 1990) and bee bread (Combey, 2017) of stingless bees

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